Doctoral theses of the School of Electrical Engineering at Aaltodoc (external link)
Doctoral theses of the School of Electrical Engineering are available in the open access repository maintained by Aalto, Aaltodoc.
Public defence in Radio Science and Engineering, M.Sc. Mohammadjavad Shabanpoursheshpoli
From theory to practice: designing smarter surfaces to improve wireless networks.
Public defence from the Aalto University School of Electrical Engineering, Department of Electronics and Nanoengineering
Public defence from the Aalto University School of Electrical Engineering, Department of Electronics and Nanoengineering
When
–
Where
Lecture hall TU2
Event language(s)
English
The title of the thesis: Challenges and Solutions of Metasurface Based Reconfigurable Intelligent Surfaces
Thesis defender: Mohammadjavad Shabanpoursheshpoli
Opponent: Prof. Jordan Budhu, Virginia Tech, USA
Custos: Prof. Constantin Simovski, Aalto University School of Electrical Engineering
Reconfigurable Intelligent Surfaces (RISs) have emerged as a transformative technology in wireless communications, promising enhanced signal propagation, interference management, and energy efficiency.
This thesis develops novel methodologies for designing RISs with improved electromagnetic parameters. In the first part of the thesis, a key focus is done on relationships between reflection locality, physical optics, and angular stability of a uniform metasurface. We show that angular stability of a uniform metasurface is crucial for a RIS implemented as its periodically non-uniform analogue (with tunable period).
Through analytical modeling, numerical simulations, and experimental validation, our study results in such binary metasurfaces (BMSs) that possess following advantages compared to previously known ones: higher angular stability of the reflection phase, true polarization insensitivity of the scattering pattern, broader operation band, and, what is not less important, possibility to accurately predict the operation characteristics with the use of simple analytical models.
In the second part of the thesis, we aim to achieve higher scattering efficiency. With this purpose our research advances the discrete sheet impedance approach for periodically non-uniform metasurfaces of general type. We optimize their beamforming efficiency, overcoming the previously adopted limitations of conventional (diagonal matrix) techniques. A novel framework for RIS with multiple reradiation modes is developed, leveraging both unequal coefficient superposition and discrete impedance optimization.
The methodologies proposed and validated in this thesis contribute to the realization of high-performance, cost-effective RISs for future wireless networks – 6G and beyond.
Key words: RIS, Wireless communication, Angular stability, Metasurfaces, Beamforming
Thesis available for public display 10 days prior to the defence at Aaltodoc.
Contact information: Javad Shabanpour : +358 504141783
Contact:
Doctoral theses of the School of Electrical Engineering
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